From Earthly Materials, which will be published this month by Mariner Books.

Assuming 128 grams a day and a lifetime in the vicinity of seventy-five years, you’ll leave behind around three and a half metric tons of feces when you die. The volume of your urine will be closer to thirty-eight thousand liters, a bit larger than a standard twenty-foot shipping container and about double the accumulated volume of your flatulence. You’ll have made hundreds of liters of tears, though even for the most emotive of individuals, the portion derived from feelings will represent a minuscule fraction of that number. For all the hullabaloo surrounding ejaculation, the total semen production of even the most alacritous masturbator could be contained handily by a shelf of two-liter soda bottles, and though a period sometimes seems as though it will never end, you could only barely paint a closet with the three or so liters of menses produced during a lifetime. You’ll have made a great deal of mucus, though, close to a hundred thousand liters. And when Atropos snips the thread of your life, the hair from your head, measured as a single strand, will stretch more than three and a half million feet. This is what you will leave behind.

Of course, you’ll leave behind another thing: your body itself. It’s uncomfortable to think of the body in this way, in the same category as feces and hair, but despite the desires of countless theologians, the trajectory of your body’s final journey will be less like the fiery passages of the stars and more akin to those meandering pilgrimages taken by your feces and urine, your blood and vomit and tears. It will become something that must be dealt with, something that must be disposed of. We may disagree over the existence and nature of an afterlife, but not about the stench of rotting flesh.

Perhaps nothing communicates the body’s ultimate dissolution so much as the great pains we have taken to disguise it. Depending on where and when you die, you might be mummified à la Tutankhamun, your organs removed and replaced with fragrant spices and salt, your skin plastered with old receipts. Or, as is still practiced by the Toraja of Indonesia, you might be preserved and entombed and brought out once every few years for family photographs. You might be left out in the open air to live on in the form of the vultures that disembowel you, or, like the Tollund Man, you could be submitted to a peat bog upon your death so that your bones dissolve in the acidic environment while your skin remains perfectly preserved. Your body might be burned in an oven and the resulting ashes stored in a decorative urn, though these ashes are not ashes at all but tiny fragments of bone. Or a mortician might drain your blood and flush your circulatory system with a formaldehyde solution tinted with dye so that rather than appearing to your loved ones with the pallor of death, you greet them for the final time looking as though you’ve just returned from Palm Springs. Or, like the Anglo-Saxons who inspired Sir Thomas Browne’s Urne-Buriall, you might be crammed into a clay pot with your hairbrushes and rings and buried on the frontier.

All this pomp and preservation, of course, only obscures the reality of what is happening. The body is becoming waste, and no matter how large an obelisk you plant atop it, the amount of matter that’s actually left at the end of a human life is still paltry. If the eight billion people on this planet—roughly half a cubic kilometer of brains, guts, blood, bones, and mucus—were spread evenly across the terrestrial portion of Earth, the resulting layer would be about as thick as the film of tears on your eye right now. You can see why the old theologians spent so much time debating the ins and outs of bodily resurrection. Decomposition has a way of making you turn your thoughts in other directions.

What, if anything, remains? In the most purely physical sense, your body contains about five hundred megajoules of energy, enough to run a sixty-watt light bulb for one hundred days or to drive a midsize sedan a mile, or, to put things in dietary terms, roughly 120,000 calories, the equivalent of a hundred Big Mac combos. This energy, stored in the form of chemical bonds—namely as molecules of glucose, protein, and fatty acids—will remain intact after you die. It needs only to be converted into adenosine triphosphate to continue its chemical journey in the shape of another. Since no single creature will be capable of digesting your body in its entirety, the scavenging of this energy will take the form of a vast buffet. The glucose in your thigh muscle might be catabolized via glycolysis by a rat while a fungus might hydrolyze the proteins in your skin. The real prize at this feast, however, will be those molecules that most efficiently store energy, your fatty acids, so that the caloric orgy reaches its apotheosis in that fattiest of all your organs, that thing which seemed most you: your brain.

Of all the sheddings we leave behind, it’s hair that we are perhaps most inclined to preserve. Why? It may be only that the cablelike structure of keratin resists microbial degradation. Hair lasts, and so we keep it, whether in envelopes or lockets or specially made flowered china. Or maybe it just seems a little cleaner than the other things we might preserve. Or maybe it’s because we make a lot of it, about a meter every hour on our heads. Whatever the case, we do gather it. We buy Elvis’s hair and Justin Bieber’s. The Smithsonian keeps a climate-controlled collection of locks supposedly belonging to the Founding Fathers.

Maybe an essential part of our personality lives in our hair. It can tell you a great deal about a person, after all. The shorn locks of a Hindu man may tell you that he is in mourning, and the beard of a Hasid tells you that he is devout. And you will understand a crucial datum about me when I tell you that, owing to the similarities in our hairstyles, for a portion of my childhood in central Pennsylvania, I was nicknamed “Tina Turner.” To be stripped of your hair is to lose some part of who you are, which might explain why there is always something uncanny about a really good wig: even when they are removed, they still seem just slightly alive.

This may be why the hair of Emperor Tewodros II, long held in London’s National Army Museum, was repatriated to Ethiopia for burial nearly 150 years after it was taken as a souvenir following the Battle of Magdala, or why the still-luxuriant tresses of Queen Tiy, dead three thousand years, inspired such awe and attention upon their display in Egypt in the spring of 2021. And it’s this dead-aliveness that sent a committee of the United States Holocaust Memorial Museum into a yearslong dispute over how to exhibit nine kilograms of human hair from among the roughly seven thousand kilos discovered by the Red Army after the liberation of Auschwitz, hair that had been intended for the manufacture of hair-yarn socks and hair-felt stockings for the crews of the Reich’s U-boats and the employees of its railways, hair that much of the committee hoped to display as dramatically as possible, as a wall of human hair, in order to drive home the notion that the human body itself, in the eyes of the Nazi, was nothing more than matériel.

The entire seven thousand kilograms had already been on display for some time at the Auschwitz-Birkenau State Museum in Poland, in large heaps of braids and knots and tresses inside a row of glass display cases. The American museum had determined that, lacking human cells, the exhibit would receive no rabbinical objection. But when the committee met to discuss its display in Washington, “it became clear,” one staff member said, “that the members viewed human hair differently.”

“While we recognize and share with you the concern for a means to convey both dramatically and soberly the enormity of the human tragedy in the death camps,” read a staff memo composed by a number of dissenters in early 1989, “we cannot endorse the use of a wall of human hair.” It would violate the innate sanctity of the hair, they felt, and it would cause in visitors a response not so much empathetic as ghoulish. Which was true, but it was precisely this ghoulishness of the exhibit that drove the opposing perspective. As one Auschwitz survivor said, “There is nothing that speaks louder against the Nazi crimes than this hair.” Which was also true. “What is hair for most of us?” said a museum director. “It’s our mothers, it’s our lovers, it’s the thing we come close to, a spot we nestle into.” You could see photographs, shoes, suitcases, identity cards, cans of Zyklon B, could even enter a model of the gas chambers, but it was not until you were confronted with the hair of the murdered that you began to comprehend the full awfulness of what had occurred.

We know roughly what we will leave behind, how much blood and mucus and hair, but not what will become of these materials. It’s an old, deep fear: they journey on without us. “Who knows the fate of his bones,” Sir Thomas Browne noted, “or how often he is to be buried?” The crux of the argument against displaying the hair at the Holocaust Museum in Washington was never entirely clear—the anxieties the idea aroused were hard to articulate. Some said they worried that moving the hair from its original context had changed; outside Auschwitz, it could be viewed only voyeuristically. A theory emerged that it would cause in visitors an emotional numbing—the exact sort of anesthetization of the empathetic faculty that had fostered Nazism in the first place. Running deep beneath all these threads seemed to be an inchoate feeling that simply to show evil was to become its apprentice. It wasn’t even clear from day to day exactly who did and didn’t want to display the hair. In the middle of the dispute, one woman in favor of it abruptly changed her mind. She had realized that the proposed wall of hair might contain her own mother’s locks.

In the end, the committee chose not to exhibit the hair. But neither was it returned to Auschwitz. It was sent instead to a storage facility outside Washington, and a space was left open in the exhibit hall, a place where the wall of hair could one day stand, when we are ready for the way it will make us feel.